Plant Answer Line Question

Will Monarch butterflies do damage to plants if they are released in a garden at their adult stage?

Answer:

The adult Monarch butterfly eats flower nectar, not leaves (the caterpillar form eats the leaves of one plant, milkweed--Asclepias), so that should not be damaging in any way.

I would question the practice of purchasing and releasing butterflies, though. It is not a good environmental practice, and can be harmful to the released butterflies and native butterfly populations. The North American Butterfly Association has information on this issue, excerpted below.

"Most fifth graders can tell you how the magnificent Monarch butterflies migrate thousands of miles every autumn from the United States and Canada to a few small mountain tops in Mexico. There they find the right environmental conditions that allow them to survive the winter. With the advent of spring, they begin their return journey. This migratory phenomenon is truly a wonder of nature that sparks the imagination.

Now imagine tens of thousands of mixed-up Monarchs unable to find the way to their overwintering grounds. This depressing image may become a reality if the rapidly-growing fad of releasing butterflies, including Monarch butterflies, at weddings, state fairs, and other public events continues to spread. Because the released Monarchs may have come from California, for instance, where they do not migrate to Mexico, their offspring may not be able to orient properly,. Because the Monarchs were raised inside under unnatural conditions, it is possible that their delicate migratory physiology may not have been turned on.

Public interest in butterflies is increasing dramatically. We hope and expect this greater involvement with butterflies will eventually lead to much-needed support for butterfly conservation and studies, but the release of live butterflies is the dark side of this increase in popularity. Although this practice is understandable to naive newlyweds-to-be (what could be more beautiful than adding butterflies to the environment?) it is really a particularly long-lasting form of environmental pollution.

Butterflies raised by unregulated commercial interests may spread diseases and parasites to wild populations, with devastating results. Often, butterflies are released great distances from their points of origin, resulting in inappropriate genetic mixing of different populations when the same species is locally present. When it is not, a non-native species is being introduced in the area of release. At best, this confuses studies of butterfly distribution and migration; at worst, it may result in deleterious changes to the local ecology. The Hollywood Jurassic park message, "Don't fool with Mother Nature," has scientific foundations. Recently a high profile report in Science magazine found that even the careful introduction of species for biological control often causes unexpected negative results.

In addition, these releases create a commercial market for live butterflies (currently about $10/apiece), with the result that, for example, the Monarch overwintering sites in Mexico and on the California coast are now targets for poachers.

Currently, the interstate shipment of live butterflies requires a permit from the U.S. Department of Agriculture but this law is not usually enforced. In general, the Dept. of Agriculture may issue a permit for shipping any of the following species: Monarch, Painted Lady, American Lady, Red Admiral, Giant Swallowtail, Gulf Fritillary, Zebra (Heliconian), and Mourning Cloak. Shipping Red Admirals, Giant Swallowtails, Gulf Fritillaries and Zebra (Heliconians) is particularly inappropriate because they are not naturally found over much of the United States.

A solution that better serves the public interest with less regulatory burden is to ban the environmental release of commercially-obtained butterflies (we would exempt education institutions, although even here we would encourage schools to keep commercially-obtained butterflies within the confines of the school). The intentional release of native birds was outlawed in 1947. The time has come to do the same with butterflies."

Plant Answer Line Question

I have become interested in helping with the conservation of monarch butterflies, whose caterpillars feed only on milkweed. We are supposed to plant milkweed. I am also gradually converting my small Seattle garden to a native-plant garden. Do these two goals contradict each other? Are any of the milkweeds native to Seattle and vicinity? Would monarchs themselves be an exotic species here?

Answer:

It's wonderful that you want to help with butterfly conservation. Monarch butterflies are not frequently seen in the Puget Sound region and, as you may be aware, it is too cold for them to overwinter here (they need an air temperature of at least 50 degrees Fahrenheit, according to Jerry Sedenko's The Butterfly Garden [Villard Books, 1991]). However, you can do several things to make your home landscape hospitable to the pollinators we do have in our area, including not using any pesticides in your garden and persuading your friends and neighbors to refrain from using them also.

The Monarch Joint Venture project links to the Xerces Society's Milkweeds: A Conservation Practitioner's Guide which has information on milkweed species and their natural habitats. The plants recommended by the MJV for the West are Asclepias speciosa and Asclepias fascicularis but these plants may not be successful in the Puget Sound region. Both species are found mostly east of the Cascades as these maps from the USDA show. (click on the detail maps for Washington State)

The Xerces Society for Invertebrate Conservation has useful information about Western Monarchs, as well as separate pollinator conservation resources (for different types of pollinators--not Monarchs) for the Pacific Northwest.

You might be most effective in supporting the Monarch conservation effort financially but devoting your gardening efforts to conservation of species that are native to our area. Here are the Xerces Society's list of Pacific Northwest butterflies and bees.

The issue of using native plants in our urban gardens is a complex one. How do we define the native status of a plant? Sometimes the only plants available in nurseries are cultivated varieties of native species: are they still 'native?' Are plants that have naturalized in our area native? Do we have the ideal conditions in our garden to sustain native plants?

My personal outlook on this is that it's best not to think too rigidly about what is native and what is not, but instead to be vigilant about what is overly aggressive or definitively noxious and invasive, and to try to grow a diverse range of plants that will thrive without excessive watering, fertilizing, and fuss, and select plants (native and otherwise) will attract birds, beneficial insects, and local species of butterfly. Here is Washington State University Extension horticulturist Linda Chalker-Scott's essay on the topic of native plants.

Garden Tip

The popular Butterfly Bush, Buddleja davidii, has proven to be a weed. Found growing in natural areas far from any garden, Buddleja's seeds are dispersed by the wind. Oregon and Washington both list it as a noxious weed.

What is a butterfly loving gardener to do? Try Blue Mist shrub (Caryopteris x clandonensis 'Black Knight' ) as a blue/purple, summer flowing shrub substitute or at least only grow the named Buddleja cultivars or the species Buddleja globosa which may be less of a threat.

Garden Tip

By joining the North American Butterfly Association for $30 per year you will support habitat conservation and research, plus receive two magazine subscriptions to learn more about gardening to encourage butterflies. For more information go to www.naba.org or write to NABA, 4 Delaware Road, Morristown, NJ 07960. To identify butterflies and caterpillars visit the Butterflies and Moths of North America website.

Garden Tip

Want to encourage butterflies to take up residence in your garden this year? Red Osier Dogwood and willows are just a few of the plants that caterpillars eat, while adult butterflies drink the nectar from Western Mock Orange and zinnias. Read a brochure produced by the Washington chapter of the North American Butterfly Association to learn more about what plants support butterflies (pdf).For a print copy send $5 to Butterfly Gardens & Habitats, 909 Birch St., Baraboo, WI 53913 USA. Specify "Western Washington")

When first picking up the fascinating Life Histories of Cascadia Butterflies, I expected lots of lovely close-up photographs of our native butterflies. While I wasn't disappointed, the majority of the photos are of the early stages of their life histories, i.e., lots of caterpillars! The thoroughness for depicting each species is outstanding with typically five or more photos of the different larval stages. How did authors David James and David Nunnallee do it? By rearing the butterflies from eggs and photographing each stage of their development.

Robert Michael Pyle wrote the Foreword and he best describes the enormous scale of this work: "...this book is the apex of life history treatments to date. In the whole world, no other comparable region enjoys a work of this scale, ambit, and acuity for its butterfly fauna".